﻿/*
* Copyright (c) 2006-2007 Erin Catto http:
*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked, and must not be
* misrepresented the original software.
* 3. This notice may not be removed or altered from any source distribution.
*
* Converted for The Render Engine v2.0
* Aug. 4, 2010 Brett Fattori
*/

Engine.include("/physics/common/b2Settings.js");
Engine.include("/physics/common/math/b2Math.js");
Engine.include("/physics/common/math/b2Vec2.js");
Engine.include("/physics/common/math/b2Mat22.js");

Engine.include("/physics/dynamics/b2World.js");

Engine.include("/physics/dynamics/joints/b2Joint.js");
Engine.include("/physics/dynamics/joints/b2JointNode.js");


Engine.initObject("b2RevoluteJoint", "b2Joint", function() {

	// Point-to-point constraint
	// C = p2 - p1
	// Cdot = v2 - v1
	//      = v2 + cross(w2, r2) - v1 - cross(w1, r1)
	// J = [-I -r1_skew I r2_skew ]
	// Identity used:
	// w k % (rx i + ry j) = w * (-ry i + rx j)
	
	// Motor constraint
	// Cdot = w2 - w1
	// J = [0 0 -1 0 0 1]
	// K = invI1 + invI2
	var b2RevoluteJoint = b2Joint.extend({

		// internal vars
		K: null,
		K1: null,
		K2: null,
		K3: null,
	
		m_localAnchor1: null,
		m_localAnchor2: null,
		m_ptpImpulse: null,
		m_motorImpulse: null,
		m_limitImpulse: null,
		m_limitPositionImpulse: null,
	
		m_ptpMass: null,
		m_motorMass: null,
		m_intialAngle: null,
		m_lowerAngle: null,
		m_upperAngle: null,
		m_maxMotorTorque: null,
		m_motorSpeed: null,
	
		m_enableLimit: null,
		m_enableMotor: null,
		m_limitState: 0,

		constructor: function(def) {
			// The constructor for b2Joint
			// initialize instance variables for references
			this.m_node1 = new b2JointNode();
			this.m_node2 = new b2JointNode();
			//
			this.m_type = def.type;
			this.m_prev = null;
			this.m_next = null;
			this.m_body1 = def.body1;
			this.m_body2 = def.body2;
			this.m_collideConnected = def.collideConnected;
			this.m_islandFlag = false;
			this.m_userData = def.userData;
			//
	
			// initialize instance variables for references
			this.K = new b2Mat22();
			this.K1 = new b2Mat22();
			this.K2 = new b2Mat22();
			this.K3 = new b2Mat22();
			this.m_localAnchor1 = new b2Vec2();
			this.m_localAnchor2 = new b2Vec2();
			this.m_ptpImpulse = new b2Vec2();
			this.m_ptpMass = new b2Mat22();
			//
	
			//super(def);
	
			var tMat;
			var tX;
			var tY;
	
			//this.m_localAnchor1 = b2Math.b2MulTMV(this.m_body1.m_R, b2Math.SubtractVV( def.anchorPoint, this.m_body1.m_position));
			tMat = this.m_body1.m_R;
			tX = def.anchorPoint.x - this.m_body1.m_position.x;
			tY = def.anchorPoint.y - this.m_body1.m_position.y;
			this.m_localAnchor1.x = tX * tMat.col1.x + tY * tMat.col1.y;
			this.m_localAnchor1.y = tX * tMat.col2.x + tY * tMat.col2.y;
			//this.m_localAnchor2 = b2Math.b2MulTMV(this.m_body2.m_R, b2Math.SubtractVV( def.anchorPoint, this.m_body2.m_position));
			tMat = this.m_body2.m_R;
			tX = def.anchorPoint.x - this.m_body2.m_position.x;
			tY = def.anchorPoint.y - this.m_body2.m_position.y;
			this.m_localAnchor2.x = tX * tMat.col1.x + tY * tMat.col1.y;
			this.m_localAnchor2.y = tX * tMat.col2.x + tY * tMat.col2.y;
	
			this.m_intialAngle = this.m_body2.m_rotation - this.m_body1.m_rotation;
	
			this.m_ptpImpulse.Set(0.0, 0.0);
			this.m_motorImpulse = 0.0;
			this.m_limitImpulse = 0.0;
			this.m_limitPositionImpulse = 0.0;
	
			this.m_lowerAngle = def.lowerAngle;
			this.m_upperAngle = def.upperAngle;
			this.m_maxMotorTorque = def.motorTorque;
			this.m_motorSpeed = def.motorSpeed;
			this.m_enableLimit = def.enableLimit;
			this.m_enableMotor = def.enableMotor;
		},	

		GetAnchor1: function() {
			var tMat = this.m_body1.m_R;
			return new b2Vec2(	this.m_body1.m_position.x + (tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y),
								this.m_body1.m_position.y + (tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y));
		},
		
		GetAnchor2: function() {
			var tMat = this.m_body2.m_R;
			return new b2Vec2(	this.m_body2.m_position.x + (tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y),
								this.m_body2.m_position.y + (tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y));
		},
		
		GetJointAngle: function() {
			return this.m_body2.m_rotation - this.m_body1.m_rotation;
		}, 
		 
		GetJointSpeed: function() {
			return this.m_body2.m_angularVelocity - this.m_body1.m_angularVelocity;
		},
		
		GetMotorTorque: function(invTimeStep) {
			return  invTimeStep * this.m_motorImpulse;
		},
	
		SetMotorSpeed: function(speed) {
			this.m_motorSpeed = speed;
		},
	
		SetMotorTorque: function(torque) {
			this.m_maxMotorTorque = torque;
		},
	
		GetReactionForce: function(invTimeStep) {
			var tVec = this.m_ptpImpulse.Copy();
			tVec.Multiply(invTimeStep);
			//return invTimeStep * this.m_ptpImpulse;
			return tVec;
		},
	
		GetReactionTorque: function(invTimeStep) {
			return invTimeStep * this.m_limitImpulse;
		},

		PrepareVelocitySolver: function() {
			var b1 = this.m_body1;
			var b2 = this.m_body2;
	
			var tMat;
	
			// Compute the effective mass matrix.
			//b2Vec2 r1 = b2Mul(b1->m_R, this.m_localAnchor1);
			tMat = b1.m_R;
			var r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
			var r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
			//b2Vec2 r2 = b2Mul(b2->m_R, this.m_localAnchor2);
			tMat = b2.m_R;
			var r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
			var r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
	
			// this.K    = [(1/m1 + 1/m2) * eye(2) - skew(r1) * invI1 * skew(r1) - skew(r2) * invI2 * skew(r2)]
			//      = [1/m1+1/m2     0    ] + invI1 * [r1.y*r1.y -r1.x*r1.y] + invI2 * [r1.y*r1.y -r1.x*r1.y]
			//        [    0     1/m1+1/m2]           [-r1.x*r1.y r1.x*r1.x]           [-r1.x*r1.y r1.x*r1.x]
			var invMass1 = b1.m_invMass;
			var invMass2 = b2.m_invMass;
			var invI1 = b1.m_invI;
			var invI2 = b2.m_invI;
	
			//var this.K1 = new b2Mat22();
			this.K1.col1.x = invMass1 + invMass2;	this.K1.col2.x = 0.0;
			this.K1.col1.y = 0.0;					this.K1.col2.y = invMass1 + invMass2;
	
			//var this.K2 = new b2Mat22();
			this.K2.col1.x =  invI1 * r1Y * r1Y;	this.K2.col2.x = -invI1 * r1X * r1Y;
			this.K2.col1.y = -invI1 * r1X * r1Y;	this.K2.col2.y =  invI1 * r1X * r1X;
	
			//var this.K3 = new b2Mat22();
			this.K3.col1.x =  invI2 * r2Y * r2Y;	this.K3.col2.x = -invI2 * r2X * r2Y;
			this.K3.col1.y = -invI2 * r2X * r2Y;	this.K3.col2.y =  invI2 * r2X * r2X;
	
			//var this.K = b2Math.AddMM(b2Math.AddMM(this.K1, this.K2), this.K3);
			this.K.SetM(this.K1);
			this.K.AddM(this.K2);
			this.K.AddM(this.K3);
	
			//this.m_ptpMass = this.K.Invert();
			this.K.Invert(this.m_ptpMass);
	
			this.m_motorMass = 1.0 / (invI1 + invI2);
	
			if (this.m_enableMotor == false)
			{
				this.m_motorImpulse = 0.0;
			}
	
			if (this.m_enableLimit)
			{
				var jointAngle = b2.m_rotation - b1.m_rotation - this.m_intialAngle;
				if (b2Math.b2Abs(this.m_upperAngle - this.m_lowerAngle) < 2.0 * b2Settings.b2_angularSlop)
				{
					this.m_limitState = b2Joint.e_equalLimits;
				}
				else if (jointAngle <= this.m_lowerAngle)
				{
					if (this.m_limitState != b2Joint.e_atLowerLimit)
					{
						this.m_limitImpulse = 0.0;
					}
					this.m_limitState = b2Joint.e_atLowerLimit;
				}
				else if (jointAngle >= this.m_upperAngle)
				{
					if (this.m_limitState != b2Joint.e_atUpperLimit)
					{
						this.m_limitImpulse = 0.0;
					}
					this.m_limitState = b2Joint.e_atUpperLimit;
				}
				else
				{
					this.m_limitState = b2Joint.e_inactiveLimit;
					this.m_limitImpulse = 0.0;
				}
			}
			else
			{
				this.m_limitImpulse = 0.0;
			}
	
			// Warm starting.
			if (b2World.s_enableWarmStarting)
			{
				//b1.m_linearVelocity.Subtract( b2Math.MulFV( invMass1, this.m_ptpImpulse) );
				b1.m_linearVelocity.x -= invMass1 * this.m_ptpImpulse.x;
				b1.m_linearVelocity.y -= invMass1 * this.m_ptpImpulse.y;
				//b1.m_angularVelocity -= invI1 * (b2Math.b2CrossVV(r1, this.m_ptpImpulse) + this.m_motorImpulse + this.m_limitImpulse);
				b1.m_angularVelocity -= invI1 * ((r1X * this.m_ptpImpulse.y - r1Y * this.m_ptpImpulse.x) + this.m_motorImpulse + this.m_limitImpulse);
	
				//b2.m_linearVelocity.Add( b2Math.MulFV( invMass2 , this.m_ptpImpulse ));
				b2.m_linearVelocity.x += invMass2 * this.m_ptpImpulse.x;
				b2.m_linearVelocity.y += invMass2 * this.m_ptpImpulse.y;
				//b2.m_angularVelocity += invI2 * (b2Math.b2CrossVV(r2, this.m_ptpImpulse) + this.m_motorImpulse + this.m_limitImpulse);
				b2.m_angularVelocity += invI2 * ((r2X * this.m_ptpImpulse.y - r2Y * this.m_ptpImpulse.x) + this.m_motorImpulse + this.m_limitImpulse);
			}
			else{
				this.m_ptpImpulse.SetZero();
				this.m_motorImpulse = 0.0;
				this.m_limitImpulse = 0.0;
			}
	
			this.m_limitPositionImpulse = 0.0;
		},
	
		SolveVelocityConstraints: function(step) {
			var b1 = this.m_body1;
			var b2 = this.m_body2;
	
			var tMat;
	
			//var r1 = b2Math.b2MulMV(b1.m_R, this.m_localAnchor1);
			tMat = b1.m_R;
			var r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
			var r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
			//var r2 = b2Math.b2MulMV(b2.m_R, this.m_localAnchor2);
			tMat = b2.m_R;
			var r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
			var r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
	
			var oldLimitImpulse;
	
			// Solve point-to-point constraint
			//b2Vec2 ptpCdot = b2.m_linearVelocity + b2Cross(b2.m_angularVelocity, r2) - b1.m_linearVelocity - b2Cross(b1.m_angularVelocity, r1);
			var ptpCdotX = b2.m_linearVelocity.x + (-b2.m_angularVelocity * r2Y) - b1.m_linearVelocity.x - (-b1.m_angularVelocity * r1Y);
			var ptpCdotY = b2.m_linearVelocity.y + (b2.m_angularVelocity * r2X) - b1.m_linearVelocity.y - (b1.m_angularVelocity * r1X);
	
			//b2Vec2 ptpImpulse = -b2Mul(this.m_ptpMass, ptpCdot);
			var ptpImpulseX = -(this.m_ptpMass.col1.x * ptpCdotX + this.m_ptpMass.col2.x * ptpCdotY);
			var ptpImpulseY = -(this.m_ptpMass.col1.y * ptpCdotX + this.m_ptpMass.col2.y * ptpCdotY);
			this.m_ptpImpulse.x += ptpImpulseX;
			this.m_ptpImpulse.y += ptpImpulseY;
	
			//b1->m_linearVelocity -= b1->m_invMass * ptpImpulse;
			b1.m_linearVelocity.x -= b1.m_invMass * ptpImpulseX;
			b1.m_linearVelocity.y -= b1.m_invMass * ptpImpulseY;
			//b1->m_angularVelocity -= b1->m_invI * b2Cross(r1, ptpImpulse);
			b1.m_angularVelocity -= b1.m_invI * (r1X * ptpImpulseY - r1Y * ptpImpulseX);
	
			//b2->m_linearVelocity += b2->m_invMass * ptpImpulse;
			b2.m_linearVelocity.x += b2.m_invMass * ptpImpulseX;
			b2.m_linearVelocity.y += b2.m_invMass * ptpImpulseY;
			//b2->m_angularVelocity += b2->m_invI * b2Cross(r2, ptpImpulse);
			b2.m_angularVelocity += b2.m_invI * (r2X * ptpImpulseY - r2Y * ptpImpulseX);
	
			if (this.m_enableMotor && this.m_limitState != b2Joint.e_equalLimits)
			{
				var motorCdot = b2.m_angularVelocity - b1.m_angularVelocity - this.m_motorSpeed;
				var motorImpulse = -this.m_motorMass * motorCdot;
				var oldMotorImpulse = this.m_motorImpulse;
				this.m_motorImpulse = b2Math.b2Clamp(this.m_motorImpulse + motorImpulse, -step.dt * this.m_maxMotorTorque, step.dt * this.m_maxMotorTorque);
				motorImpulse = this.m_motorImpulse - oldMotorImpulse;
				b1.m_angularVelocity -= b1.m_invI * motorImpulse;
				b2.m_angularVelocity += b2.m_invI * motorImpulse;
			}
	
			if (this.m_enableLimit && this.m_limitState != b2Joint.e_inactiveLimit)
			{
				var limitCdot = b2.m_angularVelocity - b1.m_angularVelocity;
				var limitImpulse = -this.m_motorMass * limitCdot;
	
				if (this.m_limitState == b2Joint.e_equalLimits)
				{
					this.m_limitImpulse += limitImpulse;
				}
				else if (this.m_limitState == b2Joint.e_atLowerLimit)
				{
					oldLimitImpulse = this.m_limitImpulse;
					this.m_limitImpulse = b2Math.b2Max(this.m_limitImpulse + limitImpulse, 0.0);
					limitImpulse = this.m_limitImpulse - oldLimitImpulse;
				}
				else if (this.m_limitState == b2Joint.e_atUpperLimit)
				{
					oldLimitImpulse = this.m_limitImpulse;
					this.m_limitImpulse = b2Math.b2Min(this.m_limitImpulse + limitImpulse, 0.0);
					limitImpulse = this.m_limitImpulse - oldLimitImpulse;
				}
	
				b1.m_angularVelocity -= b1.m_invI * limitImpulse;
				b2.m_angularVelocity += b2.m_invI * limitImpulse;
			}
		},
	
		SolvePositionConstraints: function() {
	
			var oldLimitImpulse;
			var limitC;
	
			var b1 = this.m_body1;
			var b2 = this.m_body2;
	
			var positionError = 0.0;
	
			var tMat;
	
			// Solve point-to-point position error.
			//var r1 = b2Math.b2MulMV(b1.m_R, this.m_localAnchor1);
			tMat = b1.m_R;
			var r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
			var r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
			//var r2 = b2Math.b2MulMV(b2.m_R, this.m_localAnchor2);
			tMat = b2.m_R;
			var r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
			var r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
	
			//b2Vec2 p1 = b1->m_position + r1;
			var p1X = b1.m_position.x + r1X;
			var p1Y = b1.m_position.y + r1Y;
			//b2Vec2 p2 = b2->m_position + r2;
			var p2X = b2.m_position.x + r2X;
			var p2Y = b2.m_position.y + r2Y;
	
			//b2Vec2 ptpC = p2 - p1;
			var ptpCX = p2X - p1X;
			var ptpCY = p2Y - p1Y;
	
			//float32 positionError = ptpC.Length();
			positionError = Math.sqrt(ptpCX*ptpCX + ptpCY*ptpCY);
	
			// Prevent overly large corrections.
			//b2Vec2 dpMax(b2_maxLinearCorrection, b2_maxLinearCorrection);
			//ptpC = b2Clamp(ptpC, -dpMax, dpMax);
	
			//float32 invMass1 = b1->m_invMass, invMass2 = b2->m_invMass;
			var invMass1 = b1.m_invMass;
			var invMass2 = b2.m_invMass;
			//float32 invI1 = b1->m_invI, invI2 = b2->m_invI;
			var invI1 = b1.m_invI;
			var invI2 = b2.m_invI;
	
			//b2Mat22 this.K1;
			this.K1.col1.x = invMass1 + invMass2;	this.K1.col2.x = 0.0;
			this.K1.col1.y = 0.0;					this.K1.col2.y = invMass1 + invMass2;
	
			//b2Mat22 this.K2;
			this.K2.col1.x =  invI1 * r1Y * r1Y;	this.K2.col2.x = -invI1 * r1X * r1Y;
			this.K2.col1.y = -invI1 * r1X * r1Y;	this.K2.col2.y =  invI1 * r1X * r1X;
	
			//b2Mat22 this.K3;
			this.K3.col1.x =  invI2 * r2Y * r2Y;		this.K3.col2.x = -invI2 * r2X * r2Y;
			this.K3.col1.y = -invI2 * r2X * r2Y;		this.K3.col2.y =  invI2 * r2X * r2X;
	
			//b2Mat22 this.K = this.K1 + this.K2 + this.K3;
			this.K.SetM(this.K1);
			this.K.AddM(this.K2);
			this.K.AddM(this.K3);
			//b2Vec2 impulse = this.K.Solve(-ptpC);
			this.K.Solve(b2RevoluteJoint.tImpulse, -ptpCX, -ptpCY);
			var impulseX = b2RevoluteJoint.tImpulse.x;
			var impulseY = b2RevoluteJoint.tImpulse.y;
	
			//b1.m_position -= b1.m_invMass * impulse;
			b1.m_position.x -= b1.m_invMass * impulseX;
			b1.m_position.y -= b1.m_invMass * impulseY;
			//b1.m_rotation -= b1.m_invI * b2Cross(r1, impulse);
			b1.m_rotation -= b1.m_invI * (r1X * impulseY - r1Y * impulseX);
			b1.m_R.Set(b1.m_rotation);
	
			//b2.m_position += b2.m_invMass * impulse;
			b2.m_position.x += b2.m_invMass * impulseX;
			b2.m_position.y += b2.m_invMass * impulseY;
			//b2.m_rotation += b2.m_invI * b2Cross(r2, impulse);
			b2.m_rotation += b2.m_invI * (r2X * impulseY - r2Y * impulseX);
			b2.m_R.Set(b2.m_rotation);
	
	
			// Handle limits.
			var angularError = 0.0;
	
			if (this.m_enableLimit && this.m_limitState != b2Joint.e_inactiveLimit)
			{
				var angle = b2.m_rotation - b1.m_rotation - this.m_intialAngle;
				var limitImpulse = 0.0;
	
				if (this.m_limitState == b2Joint.e_equalLimits)
				{
					// Prevent large angular corrections
					limitC = b2Math.b2Clamp(angle, -b2Settings.b2_maxAngularCorrection, b2Settings.b2_maxAngularCorrection);
					limitImpulse = -this.m_motorMass * limitC;
					angularError = b2Math.b2Abs(limitC);
				}
				else if (this.m_limitState == b2Joint.e_atLowerLimit)
				{
					limitC = angle - this.m_lowerAngle;
					angularError = b2Math.b2Max(0.0, -limitC);
	
					// Prevent large angular corrections and allow some slop.
					limitC = b2Math.b2Clamp(limitC + b2Settings.b2_angularSlop, -b2Settings.b2_maxAngularCorrection, 0.0);
					limitImpulse = -this.m_motorMass * limitC;
					oldLimitImpulse = this.m_limitPositionImpulse;
					this.m_limitPositionImpulse = b2Math.b2Max(this.m_limitPositionImpulse + limitImpulse, 0.0);
					limitImpulse = this.m_limitPositionImpulse - oldLimitImpulse;
				}
				else if (this.m_limitState == b2Joint.e_atUpperLimit)
				{
					limitC = angle - this.m_upperAngle;
					angularError = b2Math.b2Max(0.0, limitC);
	
					// Prevent large angular corrections and allow some slop.
					limitC = b2Math.b2Clamp(limitC - b2Settings.b2_angularSlop, 0.0, b2Settings.b2_maxAngularCorrection);
					limitImpulse = -this.m_motorMass * limitC;
					oldLimitImpulse = this.m_limitPositionImpulse;
					this.m_limitPositionImpulse = b2Math.b2Min(this.m_limitPositionImpulse + limitImpulse, 0.0);
					limitImpulse = this.m_limitPositionImpulse - oldLimitImpulse;
				}
	
				b1.m_rotation -= b1.m_invI * limitImpulse;
				b1.m_R.Set(b1.m_rotation);
				b2.m_rotation += b2.m_invI * limitImpulse;
				b2.m_R.Set(b2.m_rotation);
			}
	
			return positionError <= b2Settings.b2_linearSlop && angularError <= b2Settings.b2_angularSlop;
		}
			
	}, {

		resolved: function() {
	      b2RevoluteJoint.tImpulse = new b2Vec2();
		},

		tImpulse: null
		
	});
	
	return b2RevoluteJoint;

});
